A4 Terrier

I have added a decoder to a Bachmann Standard class 5MT. When testing it was found to have something ' 'catching' in the running mechanism. At the same point in each driving wheel rotation it would jerk or on a very low speed setting, stop. Checked all the steam motion to ensure there was nothing jamming. Took the motor out to examine the gearing but could not see anything obvious. Disconnected the steam motion so that only the coupling rods remained and found the fault still existed. It appears to be related in some way to the leading drive axle which at the point of the issue, is tight. Removed the wheel set and checked gauge with a back-to-back, Removed the compensator and regreased. Reassembled the loco and it remains the same with an interrupted rotation of the drivers. If it is given enough speed it is less noticeable but this is not the answer for smooth running at all speeds. Hope someone has experienced and resolved the same problem or can help me to get this right. Thanks,

Thanks all for your help. Guessed maybe the magnet has some bearing on the problem and you've confirmed that for me. Have ordered a neo.

I have a Wren A4 class that was running badly and found the problem was with the motor. Changed the armature for a rewound one, fitted new brushes and springs. The bare chassis now runs well except perhaps that it is a little faster going in reverse than it is forwards. But when the body is on it is moves only slowly. It seems the weight of a die-cast body is too much for it. Can anyone tell me what I may have done wrong or how to cure this. The only thing not changed is the magnet, could this be causing the issue? Hope someone can help me get an otherwise decent loco running as it should be.

I have been asked to look at a Hornby class 08 Diesel shunter. It is running slowly even at full power. After a few seconds it slows down even more to an unacceptable crawl. The light on my Bachmann controller dims as if there is a short of some sort but if there is I can't find it. This is a DCC ready model. Changed the blank in the DCC socket; no change. Took the TV suppressor off; no change. Finally took the DCC socket out of circuit, leads from the collectors direct to motor; no change. Don't know what to do next. Has the motor got a fault? Hope someone has seen this behaviour before and can point me in the right direction.

Mike thanks for your help. I've got it, the answer came to me in the middle of the night. Someone has resoldered or put in a replacement socket. The soldering seen only when the socket is taken out, is awful and the tabs for a number of the pins were bridged. No wonder there was a short when a decoder was added. it's so bad have ordered a new one in stead of trying to clean up. Thanks again.

Thanks for the advice. Never had the problem with Bachmann decoders and much prefer them to Hornby. I know of Zimo but never used them; it will be interesting to give one a try in the Hornby King class loco and see if it performs differently without giving an overload cut-out. Regards.

Hope that someone can help with advice regarding what appears to be strange behaviour of decoders in a Hornby DCC Ready loco. I have carried out conversions on a number of locos but never come across the problem I discovered yesterday. A Hornby Castle class and King class were on my bench to be converted for a friend. Did the Castle with a Bachmann 36-566 with no dramas. Tested, coded and it runs fine. Opened up the King Class, took out the blank and input 36-566. The loco went only a few inches then put my controller in to overload. Tried another new chip with immediate overload. Tried a TCS decoder which was OK - not great but didn't code it fully because it's too big for the loco body. Then tried a Hornby decoder and the loco runs but not very smooth at low speed, in fact downright scratchy in slow reverse; once a medium pace is reached it is good. Bachmann decoders perform on tester and cannot find a short metering all over the loco. Unsure whether this is a decoder incompatibilty fault, a loco fault or where to go next. Can anyone help or point me in the right direction.